Heat insulating and shielding glass panel

ABSTRACT

A heat insulating/heat shielding glass panel is produced by forming a functional film on a sheet of plate glass, which film is high in solar radiation reflectance, small in solar radiation absorptivity, and has emissivity of 0.20 or less, superposing another sheet of plate glass on the side of the functional film, and adhesively sealing the two sheets of plate glass, under the condition that a gap layer is provided between the two sheets of plate glass. Accordingly, there is obtained a glass panel which has a sufficient heat insulating performance and a sufficient heat shielding performance, and in which no warping is generated even when suffering the solar radiation.

This application is a 371 of PCT/JP02/04699 filed May 15, 2002.

TECHNICAL FIELD

The present invention relates to glass panels provided with heatinsulating performance and heat shielding performance optimal for use aswindowpanes in buildings.

BACKGROUND ART

A need for the high heat shielding performance of the opening portionsin a house has grown year by year. According to the standard of theperformance indication for the double layer glass for use in housespresented by “High Performance Glass Promotion Conference,” it isrequired that the solar radiation heat gain ratio be 0.51 (this valuemeans that the solar radiation heat of 51 units reaches the indoor spacebased on the solar radiation heat of 100 units) or below. Additionally,according to the next generation energy conservation standard publicizedas an announcement from Ministry of International Trade and Industry andMinistry of Construction in March of 2000, it is required that the solarradiation heat gain ratio in any of the districts III, IV, and V be 0.49(this value means that the solar radiation heat of 49 units reaches theindoor space based on the solar radiation heat of 100 units) or below,which ratio being more preferable.

As a measure for improving the heat shielding performance of the windowportions of a house, the heat ray absorbing glass has come into userecently. For example, Japanese Patent Publication No. 6-94377 andJapanese Patent Publication No. 6-102557 disclose respective types ofheat ray absorbing glass based on the combinations of special metaloxides.

Additionally, nowadays, double layer glass panels have been developedwhich have not only the heat shielding capability but also heatinsulating capability. For example, Japanese Patent No. 2882728discloses a double layer glass panel in which a sheet of colored heatray absorbing glass is arranged on the outdoor side thereof, a sheet ofclear type glass is arranged on the indoor side thereof, and a layer oflow emissivity film is formed on the indoor side of the sheet of coloredheat ray absorbing glass placed outside the room.

The above described double layer glass panel makes a too thick panedwindow glass, because it is necessary to acquire a thickness of 6 mm ormore for the air layer (or a gas layer such as an argon gas layer)between the two sheets of glass, in order to acquire a heat insulatingproperty. For example, when the thickness values of the glass sheets areeach 3 mm, and the thickness of the air layer is 6 mm, the thickness ofthe windowpane amounts to even 12 mm, so that it can hardly be used in acommon house. Accordingly, a vacuum glass panel has been developed whichis provided with a very thin vacuum layer of the order of 0.2 mm inthickness interposed between the two sheets of plate glass being thesame in constitution as those in the above described double layer glasspanel.

This type of vacuum glass panel gives a sufficiently thin windowpane,and moreover suppresses the ingression of the solar radiation heat intothe interior of a room in the hot summer daytime, and does not lose thecoolness provided by a chiller against the exterior in the nighttime, sothat the cooling efficiency is improved due to the effect of the heatray absorbing glass and the low emissivity film. Additionally, this typeof vacuum glass panel also improves the heating efficiency in winter,and hence comes into widespread use as an energy conservation typewindowpane.

The above described type of vacuum glass panel has a weak point that itis warped on receiving the solar radiation. When the rigidity of thewindow sash is strong, no problem occurs; when it is not sufficientlystrong, the sash frame is also warped by the effect of the glass panelwarping, so that the operation of opening and closing becomes unsmooth,and there is a fear that in an extreme case the sash frames chafeagainst each other to be abraded by each other.

The mechanism of the warping can be interpreted as follows. When awindowpane receives the sunlight, the sheet of the heat ray absorbingglass on the outdoor side absorbs the solar radiation energy with theresulting temperature rise and thermal expansion. On the other hand, theindoor side sheet of plate glass is low in heat ray absorption functionand in addition the solar radiation energy is absorbed by the heat rayabsorbing glass, so that the temperature rises very slightly andaccordingly the thermal expansion is very small. Additionally, thevacuum glass panel is composed of two sheets of plate glass with theperipheral portions thereof adhesively sealed and fixed using hardmaterials such as a low-melting glass and a solder. Accordingly, thedifference in thermal expansion between the two sheets of plate glassgives rise to the wrapping on the basis of the same principle as that inbimetal.

Incidentally, in the double layer glass panel, a soft material is usedas the adhesive sealing material, and accordingly the difference inthermal expansion between the two sheets of plate glass is absorbed bythe deformation of the adhesive sealing material, without involving thegeneration of the warping.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide a glass panel in whichheat insulating performance and heat shielding performance are sosufficient that no warping is generated even on receiving the solarradiation.

For the purpose of achieving the above described object, the heatinsulating/heat shielding glass panel of the present invention is a heatinsulating/heat shielding glass panel constituted so as to partition anindoor space and an outdoor space, by forming a gap layer with apredetermined spacing between a pair of sheets of plate glass, and asealed periphery portion all along the peripheries of the two sheets ofplate glass so that the gap layer is sealed into a reduced pressurestate, in which a functional film having an emissivity of 0.20 or lessis formed on the surface, in contact with the gap layer, of the outdoorside sheet of plate glass of the two sheets of plate glass; the solarradiation reflectance is 45% or less, the solar radiation absorptivitythereof is 25% or less; and the following relation holds: the solarradiation absorptivity≧(−1.02)×the solar radiation reflectance+48.5 (thesolar radiation gain ratio≦0.51).

Additionally, as for the above inequality, the following alternativerelation holds: the solar radiation absorptivity≧(−1.11)×the solarradiation reflectance+52.5 (the solar radiation gain ratio≦0.49).

FIG. 3 is a graph showing the relationship between the solar radiationabsorptivity and the solar radiation reflectance; in a sheet of plateglass provided with a functional film 5 of the preset invention, thesolar radiation reflectance thereof is 45% or less, the solar radiationabsorptivity thereof is 25% or less, and the following relation holds:the solar radiation absorptivity≧(−1.02)×the solar radiationreflectance+48.5. In this connection, for either the solar radiationabsorptivity or the solar radiation reflectance, there are two modes:one is the absorptivity (or reflectance) as observed from the filmsurface side, and the other is the absorptivity (or reflectance) asobserved from the surface of the sheet of plate glass, both being alittle different from each other; in the present invention, any one ofthese two absorptivities (or reflectances) has only to satisfy the aboveinequality.

The grounds for the above numerical restrictions are as follows:

(1) In the range where the above inequality does not hold, the solarradiation heat gain ratio of 0.51 or less cannot be achieved.

(2) With the solar radiation absorptivity exceeding 25%, the effect ofthe present invention cannot be obtained, because the warping isgenerated owing to the increased temperature difference, on receivingthe solar radiation, between the two sheets of plate glass. The solarradiation absorptivity is preferably 20% or less, and more preferably15% or less.

(3) With the solar radiation reflectance exceeding 45%, the visiblelight reflectance is often and simultaneously increased so that thedazzling appearance due to reflection is augmented, and the plate glassconcerned is not suitable for use as a windowpane in a house.

By adopting the above described constitution, the thermal expansion ofthe outdoor side sheet of plate glass when receiving the solar radiationcan be suppressed, and the solar radiation heat gain ratio of 0.51 orless can be achieved.

FIG. 4 is a graph showing the relationship between the solar radiationabsorptivity and the solar radiation reflectance; in a sheet of plateglass provided with a functional film 5 of the preset invention, thesolar radiation reflectance thereof is 45% or less, the solar radiationabsorptivity thereof is 25% or less, and the following relation holds:the solar radiation absorptivity≧(−1.11)×the solar radiationreflectance+52.5. In this connection, for either the solar radiationabsorptivity or the solar radiation reflectance, there are two modes:one is the absorptivity (or reflectance) as observed from the filmsurface side, and the other is the absorptivity (or reflectance) asobserved from the surface of the glass plate, both being a littledifferent from each other; in the present invention, any one of thesetwo absorptivities (or reflectances) has only to satisfy the aboveinequality.

The grounds for the above numerical restrictions are as follows:

In the range where the above inequality does not hold, the solarradiation heat gain ratio of 0.49 or less cannot be achieved.

With the solar radiation absorptivity exceeding 25%, the effect of thepresent invention cannot be obtained, because the warping is generatedowing to the increased temperature difference, on receiving the solarradiation, between the two sheets of plate glass. The solar radiationabsorptivity is preferably 20% or less, and more preferably 15% or less.

With the solar radiation reflectance exceeding 45%, the visible lightreflectance is often and simultaneously increased so that the dazzlingappearance due to reflection is augmented, and the plate glass concernedis not suitable for use as a windowpane in a house.

By adopting the above described constitution, the thermal expansion ofthe outdoor side sheet of plate glass when receiving the solar radiationcan be suppressed, and the solar radiation heat gain ratio of 0.49 orless can be achieved.

As the above described functional film displaying the above describedcharacteristics, there can be proposed a constitution obtained bylaminating a dielectric layer and a metal layer, for example, in such away that a first dielectric layer, a metal layer, and a seconddielectric layer are formed in the order of description on the surfaceof a sheet of plate glass; wherein the first dielectric layer is from 10to 90 nm in thickness, the metal layer is from 10 to 18 nm in thickness,and the second dielectric layer is from 10 to 60 nm in thickness.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing an example of the heatinsulating/heat shielding glass panel of the present invention;

FIG. 2 is a sectional view of the lamination structure of a functionalfilm related to an example of the present invention;

FIG. 3 is a graph showing the relationship between the solar radiationabsorptivity and the solar radiation reflectance; and

FIG. 4 is a graph showing the relationship between the solar radiationabsorptivity and the solar radiation reflectance.

BEST MODE FOR CARRYING OUT THE INVENTION

Detailed description will be made below on the present invention. Asshown in FIG. 1, in a glass panel 1, an outdoor side sheet of plateglass 2, an indoor side sheet of plate glass 3, and a gap layer 4 areintegrated, and the two sheets of plate glass are adhesively sealed allalong the peripheries thereof with a low-melting glass unshown in thefigure, a metallic solder unshown in the figure, or the like.

A layer of a functional film 5, characterizing the present invention, isformed on the gap layer 4 side of the outdoor side sheet of plate glass2. In the production of such a glass panel, at the beginning, an outdoorside sheet of plate glass 2 is prepared through forming the functionalfilm 5 on one side surface of a sheet of float glass or the like bysputtering or the like, and spacers 6 are interposed between this sheetof plate glass 2 and the indoor side sheet of plate glass 3. The spacer6 is made of a material having a compressive strength of 4.9×10⁸ Pa ormore, for example, a stainless steel (SUS304), and it is preferably asolid cylinder having a diameter ranging from 0.3 mm to 1.0 mm and aheight ranging from 0.15 mm to 1.0 mm; it is also preferable that theintervals between the individual spacers are of the order of 20 mm. Thegap layer 4 is formed between the two sheets of plate glass byadhesively sealing all along the peripheries of the two sheets of plateglass sandwiching the spacers 6 with a low-melting glass, subsequentlythe pressure in the gap layer 4 is reduced by suction of the airtherein, and the gap layer 4 is sealed closely so as to be in a state ofdisplaying an environment having a reduced pressure of 1.33 Pa or less.

The functional film 5 is a laminated film having a structure wherein adielectric layer and a metal layer constitute the main layers, forexample, a laminated film composed as a first dielectric layer/a metallayer/a second dielectric layer, or the like. Silver is recommended asthe metal for use in the metal layer among these layers; alternatively,silver doped with palladium, gold, indium, zinc, tin, aluminum, copper,or the like can also be preferably used. Additionally, the thickness ofthe metal layer is preferably from 10 to 18 nm.

As the main components of the material used in the dielectric layers,one or more than one oxides, selected from the oxides of zinc, tin,titanium, indium, and bismuth, can be used; additionally, for at leastone of the dielectric layers, one or more than one layers selected fromthe nitride layers and the oxynitride layers, containing the metals ofSi, Al, and Ti, can be used. Additionally, the thickness of the firstdielectric layer is preferably from 10 to 90 nm, while the totalthickness sum of the second dielectric layer is preferably from 10 to 60nm.

Additionally, when a dielectric layer is formed by the reactivesputtering, a sacrifice layer may be inserted into the interface moredistant from the sheet of plate glass, of the interfaces between thedielectric layers and the metal layer, which sacrifice layer consists ofthe metals or metal oxides that themselves are oxidized to prevent thedeterioration (oxidation) of the metal layer being formed. As thespecific examples of the materials to constitute the sacrifice layer,there can be cited such metals as titanium, zinc, silicon, aluminum,zinc/tin alloy, and niobium, and the oxides of these metals.Additionally, the thickness of the sacrifice layer is appropriately from1 to 5 nm. Accordingly, for example, the following constitutions areinvolved: Glass/ZnO/Ag/Ti/ZnO/SiNx; Glass/ZnO/Ag/Ti/SiNx/ZnO/SiNx;Glass/ZnO/Ag/Ti/SiNx; and the like.

Additionally, a layer of SiO₂ may be formed as the uppermost layer, thatis, the layer which is farthermost from the surface of the sheet ofplate glass. By forming the SiO₂ layer as the uppermost layer, the foamformation can be suppressed which is caused by the reaction of thefunctional film 5 with the adhesive sealing material such as alow-melting glass and a metal solder, in the adhesive sealing process;and furthermore the intrusion of the adhesive sealing material into thegap layer 4 between the sheets of plate glass 2 and 3 can be easilysuppressed. Additionally, a layer of SiO₂ may be formed as the undermostlayer, that is, the layer which is nearest to the surface of the sheetof plate glass. By forming the SiO₂ layer as the undermost layer, theeffects of the surface state of the sheet of plate glass on the layersupper than the undermost layer can be prevented, and hence the stableformation of film is made possible.

EXAMPLES

Description will be made below on the performance of the heatinsulating/heat shielding glass panel of the present invention withreference to the specific examples and comparative examples.

Example 1

The sheet of plate glass 2 of 3 mm in thickness with the functional film5 formed thereon and having the film constitution,Glass/ZnO/Ag/Ti/ZnO+SiNx (ZnO+SiNx having ZnO as the main component, andcontaining SiNx) was cut to a predetermined size, a sheet of float glassof 3 mm in thickness was prepared as the indoor side sheet of plateglass 3, the solid cylinder stainless spacers 6 of 0.5 mm in diameterand 0.2 mm in height were interposed between these two sheets of plateglass, the two sheets of plate glass were adhesively sealed all alongthe peripheries thereof with a low-melting glass, and subsequently thegap layer was depressurized and evacuated to yield a glass panel 1.

The glass panel finished as described above was subjected to evaluationunder the conditions described below.

The condition (1): the conditions of an experimental house was set tosimulate the summertime solar radiation conditions that the solarradiation heat flux was 700 kcal/m² h, the temperature outside the roomwas 30° C., and the temperature inside the room was 25° C., and thecoefficient of heat transmission (kcal/m² h° C.) was measured.Additionally, the solar radiation heat gain ratio was obtained by thecalculation based on JIS R3106 from the results of the optical propertymeasurements of the indoor side sheet and outdoor side sheet of plateglass. Furthermore, the warping of the panel was examined by visualinspection. The results thus obtained are listed in Table 1.

Examples 2 to 6

Examples 2 to 6 were the same as Example 1 in the layer constitution andthe materials of the individual layers, but the layer thickness valueswere varied from those in Example 1.

Comparative Examples 1 and 2

A sheet of plate glass with a functional film formed thereon and havingthe emissivity of 0.15 was used for the indoor side sheet of plateglass, a sheet of heat ray absorbing glass was used for the outdoor sidesheet of plate glass, and a glass panel was produced by the same methodas that in Example 1. The evaluation results for the glass panels areshown in Table 1.

The warping degrees were measured with the solar radiation flux of 700[kcal/m²·h], the temperature outside the room of 30° C., and thetemperature inside the room of 25° C.

In examples 1 to 5, the solar radiation heat gain ratios were 0.49 orless, and the warping degrees were also small. In example 6, the solarradiation heat gain ratio was 0.51 or less, and the warping degree wasalso small. On the contrary, in comparative example 1, the solarradiation heat gain ratio did not satisfy the required value; the solarradiation reflectance was low, accordingly the solar radiationtransmittance became high, and the solar radiation heat gain ratiosexceeded the required value. Additionally, the visible light reflectancealso became high, and consequently the dazzling appearance was enhancedunpreferably.

Comparative example 2 had a slightly large warping degree, but thevisible light transmittance became so low that the transmittance did notreach a level suitable for actual use as an architectural glass panel.

TABLE 1 Examples and comparative examples Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5Ex. 6 Com.ex. 1 Com.ex. 2 (Prior art) Thickness of first dielectriclayer 30 10 90 60 30 20 30 40 Outdoor side sheet [nm] of glass = Metallayer [nm] 15 10 14 15 18 13 8 25 heat ray absorbing Sacrifice layer[nm] 2 2 2 2 2 2 2 2 glass Second dielectric layer [nm] 50 10 50 60 5040 80 80 Solar radiation reflectance 37.0 40.1 37.3 36.6 44.5 34.7 20.863.3 Indoor side sheet (incident on film surface side) [%] of glass =Solar radiation absorptivity 13.7 10.7 13.1 13.7 13.2 13.3 14.9 12.3 lowemissivity (incident on film surface side) [%] glass Satisfaction ofinequality in claim 1 ∘ ∘ ∘ ∘ ∘ ∘ x ∘ Satisfaction of inequality inclaim 2 ∘ ∘ ∘ ∘ ∘ x x ∘ Visible light reflectance 13.7 15.4 18.7 19.018.5 8.5 23.0 57.6 (incident on glass surface) [%] Visible lighttransmittance [%] 78.4 74.0 73.1 73.2 72.8 82.8 71.1 33.7 Solarradiation heat gain ratio 0.48 0.48 0.48 0.48 0.42 0.50 0.62 0.26 0.47Warping degree Small Small Small Small Small Small Small Medium LargeCoefficient of heat transmission 1.1 1.1 1.1 1.1 1.0 1.1 1.2 1.0 1.3[kcal/m²h° C. ]

As above, examples have been described, but the present invention is notlimited to the above examples. For example:

(1) The glass panel of the present invention can be used not only forthe architectural use but also for a variety of uses in the casessuffering the solar radiation, such as the means of transportation(automobile windowpanes, rail car windowpanes, marine vesselwindowpanes), and the practicable windowpane and the wall material ofeither a refrigerator or a heat insulating apparatus arranged outdoors.

(2) The above described sheet of plate glass is not limited to thesheets of plate glass described in the aforementioned examples of 3 mmin thickness, but it may be a sheet of plate glass having anotherthickness, or a combination of the sheets of plate glass different fromeach other in thickness. Additionally, the type of plate glass can beoptionally selected; for example such types of plate glass includefigured glass, frosted glass (the surface thereof is processed so as tobe provided with the function to diffuse the light), wire glass, linewire glass, reinforced glass, double strength glass, low reflectanceplate glass, high transmittance plate glass, ceramic printed glass,plate glass provided with such functions as ultraviolet absorption andheat ray reflection, and the combinations thereof.

Additionally, as for the glass composition, the types of plate glass mayinclude borosilicate glass, aluminosilicate glass, various types ofpolycrystallized glass, and the like.

(3) The above described spacer is not limited to the stainless steelspacer described in the above examples; it may be a spacer made of, forexample, a metal such as iron, copper, aluminum, tungsten, nickel,chromium, titanium, and the like; an alloy such as carbon steel,chromium steel, nickel steel, nickel-chromium steel, manganese steel,chromium-manganese steel, chromium-molybdenum steel, silicon steel,brass, solder, duralumin, and the like; ceramics; or glass; in a word,the spacer material has only to be a material which is rigid enough forthe two sheets of plate glass not to come into contact with each otheron suffering an external force.

Additionally, the shape of the spacer is not limited to the solidcylinder, but it may be a sphere or a prism, and the intervals betweenthe individual spacers can be appropriately modified.

(4) The material forming the peripheral sealed portion is not limited tothe low-melting glass described in the above examples, but it may be ametal solder, and the like.

Industrial Application

The heat insulating/heat shielding glass panel of the present inventioncan achieve the high heat insulating performance and high heat shieldingperformance, by forming a functional film on the gap layer side surfaceof the outdoor side sheet of plate glass, in which film the emissivityis 0.20 or less, the solar radiation reflectance is 45% or less, thesolar radiation absorbance is 25% or less, and the following relationholds: the solar radiation absorptivity≧(−1.02)×the solar radiationreflectance+48.5; and furthermore, it is impossible that only theoutdoor side sheet of plate glass undergoes the thermal expansion due tothe heat ray absorption, and hence there is no fear that the warping dueto the difference in thermal expansion between the two sheets of plateglass occurs on the basis of the same principle as that operating inbimetal.

Accordingly, it is not necessary to use a heat ray absorbing glass asthe outdoor side sheet of plate glass, and a plate glass commonly usedfor windowpanes such as float glass suffices for the outdoor side sheetof plate glass. It is also unnecessary to add a special function to theindoor side sheet of plate glass, and hence a plate glass commonly usedfor windowpanes such as float glass can be used for the indoor sidesheet of plate glass, in the same manner as that for the outdoor sidesheet.

What is claimed is:
 1. A heat insulating/heat shielding glass panelconstituted so as to partition an indoor space and an outdoor space byforming a gap layer with a predetermined spacing between a pair ofsheets of plate glass, forming a sealed periphery portion all along theperipheries of said two sheets of plate glass, and sealing said gaplayer into a reduced pressure state characterized in that a functionalfilm having emissivity of 0.20 or less is formed on the surface, incontact with said gap layer, of the outdoor side sheet of plate glass ofsaid sheets of plate glass; the solar radiation reflectance of the sheetof plate glass with said functional film formed thereon is 45% or less;the solar radiation absorptivity of the sheet of plate glass with saidfunctional film formed thereon is 25% or less; and the followingrelation holds: the solar radiation absorptivity≧(−1.02)×the solarradiation reflectance+48.5.
 2. A heat insulating/heat shielding glasspanel constituted so as to partition an indoor space and an outdoorspace by forming a gap layer with a predetermined spacing between a pairof sheets of plate glass, forming a sealed periphery portion all alongthe peripheries of said two sheets of plate glass, and sealing said gaplayer into a reduced pressure state characterized in that a functionalfilm having emissivity of 0.20 or less is formed on the surface, incontact with said gap layer, of the outdoor side sheet of plate glass ofsaid sheets of plate glass; the solar radiation reflectance of the sheetof plate glass with said functional film formed thereon is 45% or less;the solar radiation absorptivity of the sheet of plate glass with saidfunctional film formed thereon is 25% or less; and the followingrelation holds: the solar radiation absorptivity≧(−1.11)×the solarradiation reflectance+52.5.
 3. The heat insulating/heat shielding glasspanel according to claim 1, characterized in that said functional filmis a laminated film produced by forming in order a first dielectriclayer, a metal layer, and a second dielectric layer; the thickness ofsaid first dielectric layer is form 10 to 90 nm; the thickness of saidmetal layer is from 10 to 18 nm; and the thickness of said seconddielectric layer is from 10 to 60 nm.
 4. The heat insulating/heatshielding glass panel according to claim 3, characterized in that a maincomponent of said dielectric layers comprises an oxide of one type ofmetal or more than one types of metals selected from the groupconsisting of Zn, Sn, Ti, In, and Bi; and at least one of the dielectriclayers contains a nitride layer or an oxynitride layer, containing oneor more than one types of metals selected from the group consisting ofSi, Al, and Ti.
 5. The heat insulating/heat shielding glass panelaccording to claim 3, characterized in that said metal layer is made ofAg or Ag added with Pd.
 6. The heat insulating/heat shielding glasspanel according to claim 3, characterized in that a sacrifice layer isformed between said metal layer and the second dielectric layer.
 7. Theheat insulating/heat shielding glass panel according to claim 6,characterized in that said sacrifice layer is made of Ti, Zn, Si, Al,Zn/Sn alloy, or Nb.
 8. The heat insulating/heat shielding glass panelaccording to claim 6, characterized in that the thickness of saidsacrifice layer is from 1 to 5 nm.
 9. The heat insulating/heat shieldingglass panel according to claim 1, characterized in that a SiO₂ layer isprovided as the undermost layer nearest to the surface of said sheet ofplate glass.
 10. The heat insulating/heat shielding glass panelaccording to claim 1, characterized in that a SiO₂ layer is provided asthe uppermost layer farthermost from the surface of said sheet of plateglass.
 11. The heat insulating/heat shielding glass panel according toclaim 2, characterized in that said functional film is a laminated filmproduced by forming in order a first dielectric layer, a metal layer,and a second dielectric layer, the thickness of said first dielectriclayer is form 10 to 90 nm; the thickness of said metal layer is from 10to 18 nm; and the thickness of said second dielectric layer is from 10to 60 nm.
 12. The heat insulating/heat shielding glass panel accordingto claim 2, characterized in that a SiO₂ layer is provided as theundermost layer nearest to the surface of said sheet of plate glass. 13.The heat insulating/heat shielding glass panel according to claim 2,characterized in that a SiO₂ layer is provided as the uppermost layerfarthermost from the surface of said sheet of plate glass.